Avoiding Digestive Conditions in Performance Horses

In this third edition of nutrition management tips, we look at the types of digestive conditions performance horses are at risk of and how to avoid them.

With Horse of the Year less than a month away, we’re deep in competition season with most horses almost reaching their peak of fitness. The stress and travel that comes with high performance often increases the risk of digestive conditions, however adopting various daily management techniques can reduce the risk significantly, improving wellbeing and performance. 

The equine gastro-intestinal tract is a high-functioning structure that, when healthy, is extremely effective at digestion, energy conversion and nutrient absorption. However, certain aspects of equine gut design can increase the risk of digestive conditions. The most common digestive problems seen in sport horses are gastric ulcers which mainly occur in the stomach and hindgut acidosis which can affect the large intestine, caecum and colon. 

Both gastric ulcers and hindgut acidosis are common in all horses, however they are particularly high in performance horses. While there are many contributing factors, both conditions generally occur due to stress and incorrect feeding practices. Diagnosis can be tricky as both conditions can display similar symptoms and to make diagnosis even more difficult, the conditions can also be asymptomatic, meaning no outward signs are displayed. However common signs include inappetance, grumpy behaviour, loose manure, mild colic and underperformance. 

Gastric ulcers mainly occur in the upper squamous region of the stomach. While they can occur in the lower glandular region, they are more common in the upper portion as this area doesn’t have a mucous layer or secrete bicarbonate for protection. Horses produce gastric acid at a constant rate and stomach pH can decrease quickly if the horse does not eat frequently. Meal feeding and prolonged periods without access to forage is the number one cause of ulcers, as consumption of forage stimulates saliva production which contains bicarbonate to buffer gastric acid and protect the non-glandular section of the stomach. At least 1.5% of the horse’s body weight in forage fed at a consistent rate is required for ulcer prevention. When travelling and away from home, it is important to ensure the horse consumes fibre at least every four hours. Lucerne chaff and hay are great fibre sources for ulcer prevention as the higher calcium assists with gastric buffering. Providing a handful of lucerne chaff prior to work is a great way of preventing gastric acid splash which is one of the main contributing factors to ulceration. 

Diets higher in grain can also contribute to the risk of ulcers as grain and concentrate feeds have less of a buffering effect on the stomach and increase gastrin production, the hormone that stimulates gastric acid production. Processed grains such as the steam-flaked or pelletised grains used in NRM and McMillan feeds are more digestible than raw or cracked grains and can decrease this risk.  

Hindgut acidosis has two major causes; over-consumption of high starch concentrates or pastures rich in sugars known as fructans. The delicate array of microbes that reside in the hindgut are dedicated to fibre digestion. Fermentation and microbial disturbance and a drop in pH occurs when undigested starch and sugars escape digestion in the small intestine and overflow into the hindgut.  

The limited capacity of the stomach and small intestine means this can happen easily and keeping grain meals small is highly important in preventing this condition occurring. Recommendations are to feed no more than 2.5kgs of grain or concentrate feed per meal to an average 500kg horse.  

Dietary changes can also cause microbial disruption and contribute to hindgut acidosis. Therefore care must be taken when travelling and away from home. Maintaining as consistent a diet as possible is recommended, including taking hay and feeds from home. Different pastures at events can cause disturbances, especially if they are rich and high in fructans. The most common sign of hindgut acidosis is loose manure, however it can also be displayed through mild colic, general discomfort and poor performance. For at risk horses, a hindgut balancer such as KERx EquiShure can be extremely helpful to feed in the week prior to and after an away from home competition.  

Horses at risk of digestive conditions would often benefit from diets lower in grains that provide energy for work and weight maintenance through fibre and fat. Some options of feeds formulated with these energy sources include McMillan Grain Free, Muscle Relieve and NRM Low GI Sport. KER Equi-Jewel is a great option for a high fat low starch conditioning supplement. Equi-Jewel also now contains a new ingredient called Buffered Mineral Complex (BMC) from Kentucky Equine Research, shown to buffer the stomach and hindgut to prevent these conditions. 

For more information or questions on avoiding digestive conditions in your horse get in touch with your local NRM and McMillan Equine representative. 

Article supplied by Luisa Wood,  

Equine Nutritionist 

0278097846